CN105591625A - LNA and LNA signal amplification method by LNA - Google Patents

Abstract

The invention relates to the communication field and discloses an LNA and an LNA signal amplification method by the LNA. The LNA comprises an input impedance-matching amplification circuit and an output resonance frequency-selection circuit. The input impedance-matching amplification circuit is connected with the output resonance frequency-selection circuit and used for inputting signals with two different frequencies and performing impedance-matching and amplification. The output resonance frequency-selection circuit is used for outputting signals with at least two different frequencies subjected to impedance-matching and amplification based on frequencies. The LNA and an LNA signal amplification method by the LNA have following beneficial effects: the LNA can be used for amplifying signals with at least two different frequencies by adoption of a novel circuit structure and an implementation scheme; if the LNA is applied to a radio frequency front end of a GNSS multi-mode multi-frequency receiver so that the radio frequency front end of the GNSS multi-mode multi-frequency receiver is compatible with all frequency bands of GNSS; and the radio frequency front end adopts a small chip and is low in cost.

Description

A kind of method that LNA and this LNA amplify signal

Technical field

The present invention relates to the communications field, particularly a kind of LNA (LowNoiseAmplifier, low noiseAcoustic amplifier) and this LNA method that signal is amplified.

Background technology

At present, GNSS (GlobalNavigationSatelliteSystem, GPS)The RF spot using when work is as shown in table 1.

Table 1

GNSS pattern	Frequency	Unit (megahertz)
			GPS L1	1575.42	MHz
Galileo	1575.42	MHz
			BeiDou B1	1561.098	MHz
BeiDou B2	1207.14	MHz
			BeiDou B3	1268.52	MHz
Glonass	1601.718	MHz

Wherein, GPSL1 is used by the satellite navigation system of the U.S., and operating frequency is 1575.42MHZ; GalileoSatellite navigation system by European Union is used, and operating frequency is also 1575.42MHZ; BeiDou (Big Dipper) B1,BeiDouB2 and BeiDouB3 are used by Chinese satellite navigation system, and operating frequency is respectively 1561.098Megahertz, 1207.14 megahertzes and 1268.52 megahertzes; Glonass is made by Muscovite satellite navigation systemWith, operating frequency is 1601.718 megahertzes.

At present, radio-frequency transmitter product on the market can be supported GPSL1, BeidouB1, Galileo simultaneouslyAnd Glonass, wherein, Galileo and Glonass connect with the frequency ratio of GPSL1 and BeidouB1 respectivelyClosely, still, this radio-frequency transmitter can not be supported BeidouB2 and the BeidouB3 that frequency is lower simultaneously. AlsoTo say, radio-frequency transmitter of the prior art can only receive frequency at the signal of 1.5MHz～1.6MHz, cannotThe BeidouB2 that reception frequency is lower and the signal of BeidouB3.

Radio-frequency transmitter comprises antenna and radio-frequency front-end, and wherein, antenna is for reception or transmitted signal, orderBefore have single-frequency reception antenna, also have multifrequency reception antenna, that is to say, antenna can be realized simultaneously and to receive notThe function of same frequency; Radio-frequency front-end comprises LNA and IQ (In-phaseQuadrature, inphase quadrature signal)Frequency mixer, being mainly used in realizing the part that radio frequency amplifies is LNA, IQ frequency mixer is for mixing. And prior artIn LNA adopt be written into the circuit arrangement setting out, specifically as shown in Figure 1, such LNA can only amplify GPSL1,The radiofrequency signal that these frequencies of BeidouB1, Galileo and Glonass are identical or approaching can not be amplified simultaneouslyThe BeidouB2 that another kind of frequency is lower and the radiofrequency signal of BeidouB3, so just cause in prior artRadio-frequency transmitter can only receive frequency at the signal of 1.5MHz～1.6MHz, cannot receive frequency lowerThe signal of BeidouB2 and BeidouB3.

At present, support all frequency ranges of GNSS if realize radio-frequency transmitter product simultaneously, need to adopt two coversThe scheme of chip and Geng Duo peripheral component, that is to say and need to increase a LNA and some peripheral first devices againPart, can make like this radio-frequency front-end area become larger, in addition, the price of these peripheral components is alsoMore expensive, therefore can make the cost of whole radio-frequency front-end uprise.

Summary of the invention

The invention provides a kind of method that LNA and this LNA amplify signal, this LNA can be by two kinds of differencesThe signal of frequency amplifies simultaneously, if this LNA is applied to the radio-frequency front-end of GNSS multimode multi-frequency receiver,Can make the radio-frequency front-end support of GNSS multimode multi-frequency receiver receive all frequency ranges of GNSS, and before this radio frequencyThe chip area that end adopts is little, and cost is low.

For addressing the above problem, the invention provides a kind of LNA, comprise input impedance coupling and amplify electricityRoad (1) and export resonance frequency selection circuit (2); Described input impedance coupling and amplifying circuit (1) and instituteStating export resonance frequency selection circuit (2) is connected;

Described input impedance coupling and amplifying circuit (1) are for by defeated the signal of at least two kinds of different frequenciesAfter entering, carry out impedance matching and amplify and process; Described export resonance frequency selection circuit (2) is for inciting somebody to action according to frequencyImpedance matching and the signal that amplifies at least two kinds of different frequencies after treatment are exported respectively.

Embodiments of the present invention also provide a kind of side that carries out signal amplification according to LNA as aboveMethod, comprising:

To after the signal input of at least two kinds of different frequencies, carry out impedance matching and amplify and process;

According to frequency by impedance matching and to amplify the signal of at least two kinds of different frequencies after treatment respectively defeatedGo out.

Embodiments of the present invention in terms of existing technologies, can be to the letter of at least two kinds of different frequenciesNumber input after carry out impedance matching and amplify process; And then according to frequency, impedance matching and amplification are processedAfter the signal of at least two kinds of different frequencies export respectively, realized the signal of multi-frequency carried out simultaneouslyThe function of amplifying. If this LNA is applied to the radio-frequency front-end of GNSS multimode multi-frequency receiver, canMake the radio-frequency front-end support of GNSS multimode multi-frequency receiver receive all frequency ranges of GNSS, and this radio frequencyThe chip area that front end adopts is little, and cost is low.

Preferably, in the circuit structure of the LNA of described single-input single-output, described input impedance coupling and puttingLarge circuit (1) comprises direct current DC coupling inductance (L11), exchanges AC coupling capacitance (C11), the first transistorAnd transistor seconds (M12) (M11); Described export resonance frequency selection circuit (2) comprise multiplexing inductance (LL),The first variable capacitance (C_h) and the second variable capacitance (C_l)；

The positive pole of described AC coupling capacitance (C11) is connected with the input of described LNA; Described DC couplingOne end ground connection of inductance (L11), the negative pole of the other end and described AC coupling capacitance (C11) and described the first crystalline substanceThe source electrode of body pipe (M11) is connected, and the grid of described the first transistor (M11) connects bias voltage Vbias,The drain electrode of described the first transistor (M11) is connected with the source electrode of described transistor seconds (M12); Described multipleWith inductance (LL), described the first variable capacitance (C_h) and described the second variable capacitance (C_l) be connected in parallel;The described first end being connected in parallel is connected with the drain electrode of described transistor seconds (M12), and as described LNAOutput; Described the second end being connected in parallel is connected with the grid of described transistor seconds (M12), andBe connected to supply voltage VDD.

Compared with prior art, in the present invention, the circuit of LNA is improved the input of the LNA after improvingIn impedance matching circuit, M11 adopts the wideband impedance match mode of grid altogether, and amplifying circuit M11 and M12 adopt common sourceThe connected mode of grid, can increase isolation altogether, and output adopts high-performance inductance multiplexing scheme, makes to improve itAfter radio-frequency front-end do not need to increase again chip and just can realize the signal that receives all frequency ranges of GNSS, realize1.2GHz～1.6GHz frequency coverage, receives covering frequence wide, impedance matching performance, noiseproof feature and lineProperty degree better performances, low in energy consumption, overall applicability chip area is little.

Preferably, described the first variable capacitance (C_h) comprising: the first inductance (L0), the 3rd transistor(M21), the first electric capacity (C0), the second electric capacity (C1), described the second variable capacitance (C_l) comprising:The second inductance (L1), the 4th transistor (M22), the 3rd electric capacity (C2) and the 4th electric capacity (C3);

The first end of described the first inductance (L0) is connected with digital control word, the second end and described the 3rd crystalline substanceThe grid of body pipe (M21) is connected, the drain electrode of described the 3rd transistor (M21) and described the first electric capacity (C0)Negative pole be connected, source electrode is connected with the positive pole of described the second electric capacity (C1), described the first electric capacity (C0)Positive pole be connected with described VDD, the drain electrode of described transistor seconds (M12) and described the second electric capacity (C1)Negative pole be connected with the output of described LNA;

The first end of described the second inductance (L1) is connected with described digital control word, the second end and describedThe grid of four transistors (M22) is connected, the drain electrode of described the 4th transistor (M22) and described the 3rd electricityThe negative pole that holds (C2) is connected, and source electrode is connected with the positive pole of described the 4th electric capacity (C3), described the 3rd electricityThe positive pole that holds (C2) is connected with described VDD, the drain electrode of described transistor seconds (M12) and described the 4th electricityHolding the negative pole of (C3) and the output of described LNA is connected.

As a further improvement on the present invention, in the time of specific implementation, first can in export resonance frequency selection circuitPower transformation is held and the second variable capacitance can pass through the company of an inductance, a transistor and two electric capacity respectivelyThe relation of connecing realizes, and the first variable capacitance and the second variable capacitance realized like this can meet radio-frequency front-endPVT (ProcessVoltageTemperature, process voltage temperature) yield rate, can be by twoOutput after the signal of different frequency amplifies, can guarantee that this export resonance frequency selection circuit meets index request.

Brief description of the drawings

Fig. 1 is the structural representation of LNA of the prior art;

Fig. 2 is according in the radio-frequency front-end of the GNSS multimode multi-frequency receiver in first embodiment of the inventionThe electrical block diagram of LNA;

Fig. 3 is the structure of radio-frequency front end schematic diagram of GNSS multimode multi-frequency receiver of the prior art;

Fig. 4 is the electric circuit constitute figure according to LNA in second embodiment of the invention;

Fig. 5 is according to the first variable capacitance in LNA in second embodiment of the invention and the second variable capacitancePhysical circuit composition diagram;

Fig. 6 is by physical circuit composition diagram and the figure of the first variable capacitance shown in Fig. 5 and the second variable capacitanceThe circuit diagram of the input impedance coupling of front end and the amplifying circuit LNA after linking together in 4;

Fig. 7 is the electric circuit constitute figure according to another kind of LNA in second embodiment of the invention;

Fig. 8 is the electric circuit constitute figure according to LNA in third embodiment of the invention;

Fig. 9 be according in third embodiment of the invention according to described in first, second or the 3rd embodimentLNA method that signal is amplified.

Detailed description of the invention

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing to thisBright each embodiment is explained in detail. But, persons of ordinary skill in the art may appreciate thatIn the each embodiment of the present invention, in order to make reader understand the application better, many technology are proposed thinJoint. But, even without these ins and outs and the many variations based on following embodiment and amendment,Also can realize the each claim of the application technical scheme required for protection.

The first embodiment of the present invention provides a kind of LNA, as shown in Figure 2, comprising:

Input impedance coupling and amplifying circuit and export resonance frequency selection circuit; Input impedance coupling and amplification electricityRoad is connected with export resonance frequency selection circuit; Input impedance coupling and amplifying circuit are used at least two kinds of differencesAfter the signal input of frequency, carry out impedance matching and amplify and process; Export resonance frequency selection circuit is used for according to frequentlyRate is exported impedance matching and the signal that amplifies at least two kinds of different frequencies after treatment respectively.

The radio-frequency front-end of GNSS multimode multi-frequency receiver of the prior art, as shown in Figure 3, before radio frequencyEnd comprises antenna, LNA and IQ frequency mixer, and the input of LNA is connected with the antenna of receiver, LNA'sOutput is connected with the input of IQ frequency mixer. Because GNSS always has the radiofrequency signal of two frequency ranges, and thisLNA in invention at least can amplify the radiofrequency signal of processing two frequency ranges, if by the LNA in the present inventionUse the radio-frequency front-end at GNSS receiver, can make GNSS receiver can receive GNSS full rangeThe signal of section, realizes 1.2GHz～1.6GHz frequency coverage, makes GNSS receiver have reception multimodeThe function of multi-frequency radio frequency signal, meanwhile, receives covering frequence and broadens.

Embodiments of the present invention in terms of existing technologies, can be to the letter of at least two kinds of different frequenciesNumber input after carry out impedance matching and amplify process; And then according to frequency, impedance matching and amplification are processedAfter the signal of at least two kinds of different frequencies export respectively, realized the signal of multi-frequency carried out simultaneouslyThe function of amplifying.

It should be noted that, the circuit structure of LNA is single-input single-output structure or double-input double-output structure. ThisBright the second embodiment provides the particular circuit configurations figure of a kind of LNA, and this LNA is single-input single-output structure,Be that LNA is the structure of an output of an input. The second embodiment is the concrete reality of the first embodimentExecute example, as shown in Figure 4, LNA comprises input impedance coupling and amplifying circuit 1 and defeated to the internal circuit of LNAGo out resonant selecting frequency circuit 2; Wherein, input impedance coupling and amplifying circuit 1 comprise DC (DirectCurrent, direct current) coupling inductance L11, AC (AlternatingCurrent, alternating current) couplingClose capacitor C 11, the first transistor M11 and transistor seconds M12; Export resonance frequency selection circuit 2 comprises multipleWith inductance LL, the first variable capacitance C_hAnd the second variable capacitance C_l. In input impedance matching circuit, M11For common grid connected mode; M11 and M12 form amplifying circuit, and M11 and M12 are the connection side of common grid common sourceFormula, can increase isolation like this; Export resonance frequency selection circuit 2 adopts high-performance inductance multiplexing scheme.

Concrete, the positive pole of AC coupling capacitance C11 is connected with the input of LNA, DC coupling inductance L11One end ground connection, the source electrode phase of the other end and negative pole and the first transistor (M11) of AC coupling capacitance (C11)Connect, the grid of the first transistor M11 connects bias voltage Vbias, the drain electrode of the first transistor M11 withThe source electrode of transistor seconds M12 is connected, multiplexing inductance L L, the first variable capacitance C_hAnd second variable capacitanceC_lBe connected in parallel, the first end being connected in parallel is connected with the drain electrode of transistor seconds (M12), and as LNAOutput; The second end being connected in parallel is connected with the grid of transistor seconds (M12), and is connected to electricitySource voltage VDD.

AC coupling capacitance C and DC coupling inductance L all adopt sheet external component, suppose that input impedance is Zin,Zin can be expressed as:

$\mathrm{Zin}=\frac{1}{\mathrm{sC}}+\frac{1}{\mathrm{gm}}//\mathrm{sL}$

s＝jω

Wherein, C is the capacitive reactance of AC coupling capacitance, and L is the induction reactance of DC coupling inductance, and s=j ω is signalComplex frequency, j represents imaginary part, and ω represents angular frequency, and gm represents the amplification coefficient of amplifier tube, as C and LWhen enough large, according to the representation formula of Zin, input practical impedance is approximately equal to 1/gm, with capacitive reactance, senseAnti-impact is little, can realize the wideband impedance match of 1.2GHz～1.6GHz.

In addition the input resistance that input impedance coupling, and amplifying circuit can also consist of resistance feedback formAnti-coupling and amplifying circuit substitute, but such input impedance coupling and the comparison of amplifying circuit noiseproof featurePoor. Adopting input impedance coupling and the amplifying circuit of resistance feedback form composition is prior art, at this notRepeat.

As shown in Figure 4, export resonance frequency selection circuit 2 comprises multiplexing inductance L L, the first variable capacitance C_hWithThe second variable capacitance C_l，C_hAnd C_lCan switch according to low-and high-frequency self adaptation. Wherein LL and C_hCompositionLoop is for choosing signal higher frequency; LL and C_lThe loop of composition is for lower by frequencySignal chooses. Completing full frequency band with GNSS is below received as example export resonance frequency selection circuit is describedOperation principle:

If this LNA is applied to the radio-frequency front-end of the receiver of GNSS, receive in order to realize full frequency band,C can be set_hAnd C_lThe centre frequency ω of the resonant frequency calculating_hAnd ω_lBe respectively 1580MHZ and1230MHZ makes C simultaneously_hAnd C_lMeet the following C of relation_l＝1.28C_h。

$1.6\mathrm{GHz}=2\mathrm{\π}\sqrt{\mathrm{LL}\·C_l}$

${\mathrm{\ω}}_l=\frac{1}{2\mathrm{\π}\sqrt{\mathrm{LL}\·C_l}}$

$\frac{C_l}{C_h}={\left(\frac{{\mathrm{\ω}}_h}{{\mathrm{\ω}}_l}\right)}^2={\left(\frac{1580}{1230}\right)}^2=1.28$

Wherein, ω_hFor being C according to capacitive reactance_hThe resonant frequency that calculates of electric capacity, ω_lFor according to capacitive reactance beingC_lThe resonant frequency that calculates of electric capacity, π represents pi.

When signal is by LL and C_hTime, by changing C_hCapacitance, can change resonant frequency, fromAnd change frequency-selecting frequency, in the time selecting the high-frequency signal of 1.6GHz left and right, can regulate C_h, make C_hFullFootThereby the high-frequency signal that can be by frequency 1.6GHz left and right is selected; Work as letterNumber by LL and C_lTime, by changing C_lCapacitance, can change resonant frequency, thus change frequency-selectingFrequency, in the time selecting the low frequency signal of 1.2GHz left and right, can regulate C_l, make C_lMeetThe low frequency signal that can be by frequency 1.2GHz left and right is selected.

In like manner, can adjust C_hAnd C_lCapacitance, this LNA is applied to other multimode multi-frequency ringIn border, the frequency of two or more signals is amplified to processing.

Concrete, as shown in Figure 5, in the time of specific implementation, the first variable capacitance C_hComprise: the first inductanceL0, the 3rd transistor M21, the first capacitor C 0 and the second capacitor C 1; The second variable capacitance C_lComprise: theTwo inductance L 1, the 4th transistor M22, the 3rd capacitor C 2 and the 4th capacitor C 3, wherein, C2=2C0.

Wherein, the first end of the first inductance L 0 is connected with digital control word, the second end and the 3rd transistorThe grid of M21 is connected, and the drain electrode of the 3rd transistor M21 is connected with the negative pole of the first capacitor C 0, source electrode andThe positive pole of the second capacitor C 1 is connected, and the positive pole of the first capacitor C 0 is connected with VDD, transistor seconds M12Drain electrode and second negative pole of capacitor C 1 and the output of LNA be connected.

The first end of the second inductance L 1 is connected with digital control word, the second end and the 4th transistor M22'sGrid is connected, and the drain electrode of the 4th transistor M22 is connected with the negative pole of the 3rd capacitor C 2, source electrode and the 4th electricityThe positive pole that holds C3 is connected, and the positive pole of the 3rd capacitor C 2 is connected with VDD, the drain electrode of transistor seconds M12And the 4th the negative pole of capacitor C 3 and the output of LNA be connected.

Fig. 6 mates the export resonance frequency selection circuit shown in Fig. 5 and amplifies electric with the input impedance of front endCircuit diagram after road links together.

Compared with prior art, the present invention to the input impedance matching circuit of LNA in M11 adopt altogether gridWideband impedance match mode, amplifying circuit M11 and M12 adopt the connected mode of cascade, canIncrease isolation, output adopts high-performance inductance multiplexing scheme, this LNA is applied in the receiver of GNSS,Can make the radio-frequency front-end of GNSS after improving not need to increase again chip and just can realize receptionThe signal of all frequency ranges of GNSS, realizes 1.2GHz～1.6GHz frequency coverage, receives covering frequence wide,Impedance matching performance, noiseproof feature and linearity better performances, low in energy consumption, overall applicability chip areaLittle. In addition,, in the time of specific implementation, the first variable capacitance and the second variable capacitance respectively can be by oneThe annexation of inductance, a transistor and two electric capacity realizes, the first variable capacitance of realizing like thisCan meet the PVT yield rate of radio-frequency front-end with the second variable capacitance, can be by the letter of two different frequenciesNumber amplify after output, can guarantee that this export resonance frequency selection circuit meets index request.

In addition, export resonance frequency selection circuit can also adopt the high-performance inductance outside chip to realize, this areaTechnical staff can realize this circuit completely according to this prompting, do not repeat at this.

Further, by increasing the number of the capacitor array in export resonance frequency selection circuit, of the present inventionLNA can realize the signal of multiple frequencies is amplified to processing. Specifically as shown in Figure 7. Shown in Fig. 7The export resonance frequency selection circuit of LNA in capacitor array comprise multiple variable capacitance C_h、C_lCm andCn, wherein, each variable capacitance can be realized the function that the signal of a concrete frequency is selected, figureIn capacitor array comprise plural variable capacitance, therefore, the LNA shown in Fig. 7 can be by twoThe signal of individual above different frequency amplifies and selects. It should be noted that, when specific implementation, electric capacity battle arrayIn row, the physical circuit of each variable capacitance can, with reference to the relevant portion in figure 6, not repeat at this.

Third embodiment of the invention provides the particular circuit configurations figure of a kind of LNA, and this LNA many for entering moreThe differential configuration going out, LNA is the structure of the multiple outputs of multiple inputs, specifically as shown in Figure 8. The 3rdEmbodiment is the specific embodiment of the first embodiment, the operation principle of the LNA that present embodiment disclosesSimilar with the second embodiment, does not repeat at this.

It is a kind of according to described in first, second or the 3rd embodiment that four embodiment of the invention providesLNA carries out the method for signal amplification, as shown in Figure 9, comprising:

901, will after the signal input of at least two kinds of different frequencies, carry out impedance matching and amplify and process.

902, according to frequency, impedance matching and the signal that amplifies at least two kinds of different frequencies after treatment are dividedShu Chu not.

Present embodiment is the embodiment of the method corresponding with first, second or the 3rd embodiment, according toOne or second LNA described in embodiment carry out signal amplification method can with reference to first, second orAssociated description and analysis to LNA circuit working principle in three embodiments, do not repeat at this.

Embodiments of the present invention in terms of existing technologies, can be to the letter of at least two kinds of different frequenciesNumber input after carry out impedance matching and amplify process; And then according to frequency, impedance matching and amplification are processedAfter the signal of at least two kinds of different frequencies export respectively, realized the signal of multi-frequency carried out simultaneouslyThe function of amplifying. If this LNA is applied to the radio-frequency front-end of GNSS multimode multi-frequency receiver, can makeThe radio-frequency front-end support of GNSS multimode multi-frequency receiver receives all frequency ranges of GNSS, and this radio-frequency front-endThe chip area adopting is little, and cost is low.

Persons of ordinary skill in the art may appreciate that the respective embodiments described above be realize of the present invention concreteEmbodiment, and in actual applications, can do various changes to it in the form and details, and not inclined to one sideFrom the spirit and scope of the present invention.

Claims (6)

1. a low-noise amplifier LNA, is characterized in that, comprises input impedance coupling and amplifies electricityRoad (1) and export resonance frequency selection circuit (2); Described input impedance coupling and amplifying circuit (1) andDescribed export resonance frequency selection circuit (2) is connected;

Described input impedance coupling and amplifying circuit (1) are for by defeated the signal of at least two kinds of different frequenciesAfter entering, carry out impedance matching and amplify and process; Described export resonance frequency selection circuit (2) is for according to frequencyImpedance matching and the signal that amplifies at least two kinds of different frequencies after treatment are exported respectively.

2. LNA according to claim 1, is characterized in that, the circuit structure of described LNA isSingle-input single-output structure or double-input double-output structure.

3. LNA according to claim 2, is characterized in that, at the LNA of described single-input single-outputCircuit structure in, described input impedance coupling and amplifying circuit (1) comprise direct current DC coupling inductance(L11), exchange AC coupling capacitance (C11), the first transistor (M11) and transistor seconds (M12);Described export resonance frequency selection circuit (2) comprises multiplexing inductance (LL), the first variable capacitance (C_h) and secondVariable capacitance (C_l)；

The positive pole of described AC coupling capacitance (C11) is connected with the input of described LNA; Described DC couplingOne end ground connection of inductance (L11), the negative pole and described first of the other end and described AC coupling capacitance (C11)The source electrode of transistor (M11) is connected, and the grid of described the first transistor (M11) connects bias voltageVbias, the drain electrode of described the first transistor (M11) is connected with the source electrode of described transistor seconds (M12);Described multiplexing inductance (LL), described the first variable capacitance (C_h) and described the second variable capacitance (C_l) parallel connectionConnect; The described first end being connected in parallel is connected with the drain electrode of described transistor seconds (M12), and conductThe output of described LNA; The grid of described the second end being connected in parallel and described transistor seconds (M12)Be connected, and be connected to supply voltage VDD.

4. LNA according to claim 3, is characterized in that, described the first variable capacitance (C_h)Comprise: the first inductance (L0), the 3rd transistor (M21), the first electric capacity (C0), the second electric capacity(C1); Described the second variable capacitance (C_l) comprising: the second inductance (L1), the 4th transistor (M22),The 3rd electric capacity (C2) and the 4th electric capacity (C3);

The first end of described the first inductance (L0) is connected with digital control word, the second end and described the 3rd crystalline substanceThe grid of body pipe (M21) is connected, the drain electrode of described the 3rd transistor (M21) and described the first electric capacity (C0)Negative pole be connected, source electrode is connected with the positive pole of described the second electric capacity (C1), described the first electric capacity (C0)Positive pole be connected with described VDD, the drain electrode of described transistor seconds (M12) and described the second electric capacity (C1)Negative pole be connected with the output of described LNA;

The first end of described the second inductance (L1) is connected with described digital control word, the second end and describedThe grid of four transistors (M22) is connected, the drain electrode of described the 4th transistor (M22) and described the 3rd electricityThe negative pole that holds (C2) is connected, and source electrode is connected with the positive pole of described the 4th electric capacity (C3), described the 3rd electricityThe positive pole that holds (C2) is connected with described VDD, the drain electrode of described transistor seconds (M12) and the described the 4thThe negative pole of electric capacity (C3) is connected with the output of described LNA.

5. LNA according to claim 4, is characterized in that, described the 3rd electric capacity (C2)Capacitive reactance is 2 times of capacitive reactance of described the first electric capacity (C0).

6. a method of carrying out signal amplification according to the arbitrary described LNA of claim 1 to 5, itsBe characterised in that, comprise:

To after the signal input of at least two kinds of different frequencies, carry out impedance matching and amplify and process;

According to frequency by impedance matching and to amplify the signal of at least two kinds of different frequencies after treatment respectively defeatedGo out.